1. Field of the Invention
The present invention relates to an infrared (IR) communicator, particularly to an infrared communication device which can receive data from an IR data source without being influenced by the existence of any obstacle interrupting infrared rays between the communication device and the data source.
2. Description of the Prior Arts
A conventional infrared receiver, generally uses a single light receiving element to receive infrared rays with strong directivity radiated from multiple directions. As in an infrared communication device disclosed for example in Japanese Patent Application Laid-open No. 241444/1987, a base material for guiding infrared rays to the single light receiving element by changing the path of incident infrared rays by reflection and refraction is arranged in the periphery of the light receiving element provided in the infrared receiver. In such an infrared receiver, the infrared rays incident upon the base material advance inside therein while being reflected or refracted, so that the infrared rays are guided to the light receiving element and received.
Such conventional infrared sensor will be described with reference to FIGS. 1 and 2.
Referring first to FIG. 1, when an infrared transmitter 6 transmits an infrared ray to an infrared receiver 3, the infrared ray reaches a base material 4, which is the single base material provided in the infrared receiver 3. The infrared ray transmitted from the infrared transmitter 6 is partly reflected by the surface of the base material 4, but the remaining part of the infrared ray enters the base material 4. A part of the infrared ray incident upon the base material 4 is repeatedly reflected inside the base material 4, guided to and received by an infrared receiving section 5, which is the single receiving section provided in the infrared receiver 3.
The infrared ray transmitted from the infrared transmitter 6 is partly reflected by the surface of the base material 4, but remaining part of the infrared ray enters the base material 4. A part of the infrared ray incident upon the base material 4 is repeatedly reflected inside the base material 4, guided to and received by an infrared receiving section 5, which is the single receiving section provided in the infrared receiver 3.
Next, referring to FIG. 2, when infrared rays are transmitted from infrared transmitters 10 to an infrared receiver, 7, the infrared rays reach a base material 8 having a transparent convex lens shape, which is the single base material provided in the infrared receiver 7. Some of the infrared rays are reflected by the surface of the base material 8, but others enter the base material 8. Some of the infrared rays entering the base material 8 are refracted inside the base material 8 having the convex lens shape, further repeatedly reflected by the inner face of the base material 8, and guided to and received by an infrared receiving section 9 which is the single light receiving section of the infrared receiver 7.
The first problem with such infrared communication lies in that in the existence of an obstacle interrupting the infrared ray in space on a straight line connecting one light emitting element and one light receiving element, the infrared ray transmitted from one light emitting element cannot be received by the single light receiving element.
This is because the infrared ray transmitted from the single light emitting element and having a strong directivity is interrupted by the obstacle, so that it cannot reach the light receiving element.
The second problem lies in that even in a structure in which the light receiving element can receive infrared rays transmitted from multiple directions, if there is an obstacle interrupting the infrared rays in the space on the straight line connecting a light emitting element and a light receiving element, the infrared rays transmitted from the light emitting element cannot be received by the light receiving element.
Since the infrared ray having a strong directivity is interrupted by the obstacle before reaching the light receiving element, the infrared ray cannot be received even in the structure where the light receiving element can receive infrared rays reaching from multiple directions.
An object of the present invention is to provide an infrared receiver system which can receive infrared rays transmitted from an infrared communicator on a communication end without being influenced by obstacles in infrared communication.
Another object of the present invention is to provide an infrared communication which is not influenced by obstacles without using any special infrared communication procedure.
To attain these and other objects, the present invention provides an infrared communicator in which a light receiving element is selected which is not influenced by obstacles existing in a space between the infrared receiver system and a communication-end infrared communicator and interrupting or reflecting infrared rays, to receive the infrared rays transmitted from the communication-end infrared communicator.
Specifically, in case where the infrared transmitter of the present invention transmits an infrared ray to a communication-end infrared receiver system, the infrared receiver system of the present invention, comprises means for measuring an intensity with which the infrared ray transmitted from a light emitting element of the infrared communicator is reflected by an obstacle interrupting the infrared ray in a space between the infrared transmitter and the communication-end infrared communicator and returns to a light receiving element of the infrared communicator; means for judging which light receiving element is influenced by the interruption of the infrared ray by the obstacle; and means for selecting the light receiving element not influenced by the interruption and a reception amplifier to be connected to a demodulation circuit.
Moreover, the present invention has a characteristic that the conventional infrared communication procedure is not changed. In the measurement of the intensity with which the infrared ray is reflected by the obstacle interrupting the infrared ray in the space between the infrared communicator of the present invention and the communication-end infrared communicator and returns to the light receiving element, the infrared communicator includes means for performing the measurement in parallel with data transmission from the infrared communicator.
During the data transmission from the infrared communicator of the present invention to the communication-end infrared communicator, the light receiving element is selected which is not influenced by the obstacle existing in the space between the infrared communicator and the communication-end infrared communicator and interrupting the infrared ray. Therefore, the conventional infrared communication procedure does not need to be changed.